Cadmium base bearing metal



Patented Jan. 2 2, 1935' V UNITED STATE CADMIUM BASE BEARING METALWilliam E. McCullough, Detroit, Mich assignor to Bohn Aluminum & BrassCorporation, Detroit, Mich., a corporation of Michigan No Drawing.Application May 16, 1934,

Serial No. 725,997

3 Claims.

The invention relates to bearing metal alloys and has for its object theobtaining of a material having novel and valuable characteristics. Dueto changes in recent motor design, such as reduced 5 bearing areas,increased speed in operation and the higher temperatures, bearingsheretofore used are proving unsatisfactory. Among the alloys in use are,first, tin base babbitts. These are unsuitable, principally on accountof their low melting point. Lead base bearing metals have also been usedand have substantially higher melting points but have too low wearresistance. Leaded bronze bearing linings resist wear and have as goodheat resistance as lead base alloys, .but have a tendency to wear thecrank shafts which ordinarily have a Brinell hardness of 212-275 inmotor car engines. Alloys of cadmium base metal combined with certainother metals such as nickel, zinc, antimony, magnesium, copper and lead,have been known, but as heretofore used, have been unsatisfactory. Ihave discov-' ered that a bearing material having improvedcharacteristics can be obtained by'the use of a cadmium base with arelatively small'amount of copper and magnesium, in definite proportionand held within close limits. My invention therefore consists in thealloy as hereinafter set forth.

My improved cadmium base alloy is of the following composition:

Copper from 0.2% to 1.5%; magnesium from 0.1% to 0.75%; balance cadmium.

For steel back connecting rod bearings and bearings for similar uses, Ihave found that an alloy of copper 0.5%; magnesium 0.25% and'the balanceof cadmium, has a much longer life than an alloy of the same elementswith materially larger or smaller amountsof the copper and.

magnesium. This is doubtless for the reason that the copper andmagnesium have a hardening effeet and if too much is used the result isexcessive brittleness which decreases the length of life.

On the other hand, if smaller amounts of the copper and magnesium areused, the-alloy will be softer and not as well adapted for thesespecific bearings. However, for bearings designed for other uses, suchas for high speeds and light loads, a cadmium base alloy having smalleramounts of copper and magnesium may be satisfactory. Also, for bearingsdesigned for heavy duty, such as railway car journals, a larger amountof the hardening elements in the alloy may be used to advantage.

My improved bearing alloy has the following valuable characteristics:

1.. High compression strength compared to babbitt at varyingtemperatures up to 500 F.;

2. Greater hardness than babbitt up to 500 F.;

3. Higher melting point than babbitt not lower than 575 F.; 1

4. Ability to be bonded firmly to steel;

5. Ability to run at higher speed and temperature without undue wear ofbearing or crank shaft, and

6. Ability to give satisfactory bearing performance under conditionsthat cause tin babbitt to fail.

What I claim as my invention is:

1. A hearing alloy comprising copper 0.2% to 1.5%; magnesium 0.1% to0.75%, balance cadmm.

2. A bearing alloy comprising the following elements in substantiallythe proportions given:

Copper 0.5

3. In a steel back bearing, a bearing alloy comprising copper 0.2% to1.5%, magnesium 0.1% to 0.25% and balance of cadmium, said alloy beingfirmly bonded to the steel backing.

7 WILLIAM E. McCULLOUGH.

